I wonder if faulty stick coils could be the problem? Aside from the buzziness, my symptoms are a very rough idle, (to the point of adding throttle at stops) diminished fuel economy and in the higher rpm's the engine seems to "load up" and kinda bog down as I accelerate to the higher rpm range. It's not very pronounced but I know it's there. I am confident that the valves and TB are in good order. I don't really want to gamble prices for new stick coils at this time without having some indication that they were bad.
A few weeks late with this update but, I did go ahead and order the stick coils. After installing them, I am simply amazed at the marked improvement in performance. No more buzzy seat, pegs or hand grips. Power has increased, mpg's have improved, idle is smooth and silky, and power roll on is simply awesome. My source.....http://euromotoelectrics.com
On a running multi-cylinder internal combustion engine, vibration comes from only two basic causes:
1. Mechanical imbalance
2. Combustion imbalance
There is some inherent slight mechanical imbalance. But that is unlikely to change much over time unless you have internal transmission problems or driveline universal joint problems. If you have an oiling problem on one cylinder a heavy build up of carbon on only one piston top can cause a buzzy vibration.
Most vibration changes over time however are due to combustion imbalance. Throttle synch matches air flow (absent other obstructions), clean injectors match fuel flow, valve adjustment is critical, good spark plugs are important, etc. A significant difference in compression could be a factor.
Bottom line is that the bike probably needs a meticulous tune-up.
Edit: Ooops! I ought to look at the end of a thread before adding comments.
p.s. I hate stick coils!
Last edited by PGlaves; 10-23-2013 at 04:58 PM.
Paul Glaves - "Big Bend", Texas U.S.A
"The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
Nice description Paul.
You can further reduce the fueling imbalance by richening the mixture. The way this happens is that as you richen the mixture, the small amount of unburned O2 in a stock motor gets consumed. Once the O2 has been used up, any excess fuel in the richer of the two cylinders doesn't add power. Bottom line is that the power produced by each cylinder is then affected mostly by the air balance.
P.S. I just replaced my stick coils too. I was very surprised at the improvements in starting and running.
Coils aren't "supposed" to be a wear item, but these sticks sure do seem to have a crappy failure rate. I've replaced both of mine, too... big difference!
Just do the quick test if you are not sure. First look closely at the connection between the stick coil and the power lead. Make sure you know how to release it without wrecking the connector. Start the bike, let it idle, disconnect the power lead at the stick coil on one side, if the idle does not change, that stick coil is bad. Turn off the bike, reconnect the lead and do the other side.
It's only 2004 Oilheads that have stick coils, correct?
'12 R1200RT, '02 R1100S, '84 R80G/S
yes, 2004 ,some listed as 2005 1150's. the prior models were single spark and conventional coils
Roger, if the side would only run on the stick coil. was the conventional coil bad?
SABMWRA MOA Club#62's Flat Fixer/ current forum moderator
It's not the breaths you take, but the moments that take your breath away-D.Dillon/G. Strait
Last edited by Tennessean; 10-24-2013 at 06:20 PM. Reason: add link
A dent in my front rim turned out to be the culprit for vibration at 4500+ rpm! I had the wheel straightened and re-balanced and it made a noticeable difference.
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Rides a 1996 R1100R